Gemstone



FIG. 1 is a top/side perspective view of a gemstone having the design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a side elevation view, the design having rotational symmetryabout a main vertical axis; and,

FIG. 4 is a bottom plan view thereof.

CLAIM The ornamental design for a gemstone, as shown and described.